A number of devices and techniques for closing a hole in the side of a wall of a blood vessel made for intravascular access or other purposes have been proposed. Foams, plugs, caps and other structures have been developed for application over or within such holes, to limit or eliminate blood loss through such holes. In the realm of internal caps, seals or toggles, such a piece must be inserted through the hole, then retracted in an orientation such that the cap, seal or toggle will engage the vascular wall at points to the side of the hole. Insertion usually occurs through a cannula or other tube extending through the hole, and naturally in order to be inserted through the tube and hole such an internal piece must be smaller than the tube and hole during insertion.
Several difficulties with using such systems exist. For example, a compressed plug or cap forced into a delivery tube may be constrained by the tube, and therefore have a significant amount of force or friction between the tube and the plug or cap. Moving the plug or cap out of the tube is accordingly difficult. If a plug or cap is constrained in a compressed condition by something other than the tube, it may be easier to move the plug or cap out of the tube. However, once out of the tube, the plug or cap may not be oriented as desired, or may not properly extend or expand following insertion, e.g. the constraint holding the item in a compressed state is not overcome. If the plug or cap does not open sufficiently, it can be pulled back through the hole rather than engaging against the vessel wall. Similarly, thin or very flexible plugs or caps may not have sufficient sturdiness to hold when pulled against the vascular wall, resulting in unwanted eversion or pulling back through the hole.
Accordingly, there is needed an internal seal or anchoring member that is not only bioabsorbable and will securely anchor a closure and/or seal a hole in a vascular wall, but that will also regularly open or expand in an expected way when placed in the blood vessel. Such an item would address the problems noted above, and perhaps others.